According to an article on NeoGaf, a user has compared the graphical fidelity of Mass Effect Andromeda and it seems that it has been reduced since the reveal trailer vs. the latest trailer shown by the developers.
This is definitely what we have seen with most games when compared with their reveal vs actual game graphics. Usually, graphical downgrade is because of the current generation consoles not being able to handle the graphics or to reduce the PC specs for the game.
Mass Effect Andromeda graphics have been slightly reduced as can see from the reveal vs latest showcase, but it does not mean that the game will be completely horrible looking; it will still most likely look just fine.
Even though this downgrade isn’t at all significant and most people wouldn’t be able to tell the difference, it is still one nonetheless.